So I guess I didn't take as many photos as I thought, so I will post what I have. For the most part, this swap really wasn't that difficult with the exception of the top two bolts holding the transmission to the engine. I think those took probably 50-60% of the time just to get them out and back in. Everything else went pretty smooth.

Now this is going to be a brief overview. If you need to replace your transmission, do so at your own risk.

So first thing I actually did was lift the car to get it high enough off the ground to gain access to remove the transmission. My chock blocks lift the bottom of the wheels about 13.5 inches off the ground. It was enough clearance.

Next, I removed the exhaust. There is an oxygen sensor on each pipe, and the connector is about 8inches from the o2 sensor. Then on each pipe, there are two nuts that hold the system together as seen in the pictures. Remove them, and support the exhaust system. At the rear of the car the system is held in place with some rubber exhaust hangers. Pry the system off the hangers and rest it to the ground.

I then drained the transmission. You need a star bit to do this. Interesting fact, the new transmission does not have a drain plug. Next, I removed the cooler lines from the side of the transmission. They are located on teh driver side, and are held in place by a plastic bracket and a single bolt in the center. To fully remove the lines you also have to remove the bracket that the lines hang from which is located right near the oil filter. The first picture shows the plastic mounting bracket, the second shows the location for the carier bracket. I found it necessary to do this to gain access to the torque converter bolts.

To gain access to the torque converter bolts, there is a small access port in the engine block, right near where the cooler lines run. There are three bolts. I rotated the engine by the crank pulley and felt for the bolts. I don't have a great pic of the access port, but it is there.

Next, support the transmission and remove the transmission mount. There are four bolts that hold the mount to the body, and two bolts into the transmission. The mount can be seen picture below. It is the black metal bracket. Then disconnect the wiring harness.

I then removed the drive shaft completely. Now you could probably just remove it from the trans, but I wanted the extra space. It is connected to basically a cush drive system at the trans and the diff. There is a carrier bearing in the center that is held to the body with two bolts. The carrier bearing can be seen in the above pictures.

Now you lower the transmission a little bit to gain access to the upper two bolts. This is the biggest time consumer. These bolts also hold a bracket that the wiring harness is secured to, so they need to come out fully in order to remove the transmission.

Once they are out, raise the trans a little bit again, support the engine, and remove the lower 8 bolts. You are now ready to remove the transmission. When removing it, there is a tube connected to the top that you need to remove. Pull it back a little from the car, and slowly lower the trans. It is a somewhat stepping process where you lower and pull back a little bit. And it is out. The second picture below shows the bracket and wiring harness that caused most of the issue with removing the upper two bolts.

On the transmission, the manifold that the cooler lines is secured to needs to be moved to the new transmission. It is one bolt that holds it on. There are two gaskets on this manifold, which I reused because they looked to be in very good shape.

Now, you're ready to put the new trans in. Perform the steps in reverse.

It is necessary to use new torque converter bolts and new o-rings on the trans cooler lines.

The new trans is working well so far, shifts into fourth, now I just have to return the core and get my $700 back :)

C&C

01-13-12, 06:57 AM

Thanks for sharing. Sure looks like you did a good job; hope your repair lasts the life of the car.

M5eater

01-13-12, 07:02 AM

what did you have it out for? everything looks brand new, I don't think I spotted a single oil leak.

Angus Young

01-13-12, 09:53 AM

I'd like to see a picture of the shift linkage and the bushing that wears out if anyone has one, I have (2) 05 STS's and both clank when shifting, one wont shift into 4 anymore its so loose.

orange57

01-13-12, 12:52 PM

M5eater, the trans wouldn't shift into 4th gear. It would essentially shift form 3rd, try 4th, back to 3rd and then 5th. It was about the same cost to rebuild or replace.

I don't recal a bushing. The shift linkage is prettey simple. In the pic where i'm looking towards the back, you can see it dangling on the left side. It is held on by one nut, and like a keyed brakcet that shifts the trans. Very simple design. Next oil change I will try to get some more pics of it.

jkharnage

02-07-12, 10:53 AM

This is great info. You did a nice job with the photo's. Do you have any torque specs for the transmission bolts and drive shaft? What's the best way to fill the new transmission and ensuring it's topped off? Did you have to do any software updates for the new transmission.

orange57

02-07-12, 09:07 PM

The torque spec for the drive shaft/coupler is 63ft-lbs. The center bearing mount for the drive shaft is 37 ft-lbs. Transmission to Engine is 37 ft-lbs. Flex Plate to Torque Converter are 46 ft-lbs. Let me know if there are any other specs you need. The car is still shifting well. As far as topping it off, I didn't need to, it was factory filled, with enough fluid for the cooler as well. If you do need to add more fluid, I would suggest one of the little hand pumps from harbor freight, this would make it easy to pump the fluid up into the trans from underneath. Also no transmission updates. The system basically re-learns your driving style.

nethashem

12-27-14, 05:44 PM

sir, what you did to get the uper two bolts
i cant`t reach them at all

samson_420

12-27-14, 08:12 PM

Is this the STS that was for sale with a bad trany on CL a few months ago?

I was gonna grab that thing, didn't think it'd be that bad of a job

Thx for the pics

CadiTamer

12-28-14, 02:22 AM

Very nice write up. Would have killed to have this last year when i replaced the transmission in my car, but sadly didn't have the time to take pictures when i did it.

I can't tell if this is the V6 or the V8... Did you have to pull the intake manifold and thermostat housing to get access to the bolts at the top of the transmission? That was the only way i could get them out on my car.

PontiacV8

12-28-14, 03:34 AM

...side note: ...thread / pictures are almost 3 years old... ;)

1BadCadSTS

12-28-14, 11:13 AM

...side note: ...thread / pictures are almost 3 years old... ;)

I noticed that too. Clearly thats the car on cl a few months ago lol.

samson_420

12-28-14, 12:32 PM

I noticed that too. Clearly thats the car on cl a few months ago lol.

Damn it, lol

I so missed the date

But, it looked just like it - silver with a dead AT

1BadCadSTS

12-28-14, 03:26 PM

Very nice write up. Would have killed to have this last year when i replaced the transmission in my car, but sadly didn't have the time to take pictures when i did it.

I can't tell if this is the V6 or the V8... Did you have to pull the intake manifold and thermostat housing to get access to the bolts at the top of the transmission? That was the only way i could get them out on my car.

Badge right on the trunk deck lower left says Northstar.

----------

Damn it, lol

I so missed the date

But, it looked just like it - silver with a dead AT

All good.

orange57

12-29-14, 04:53 PM

Hey guys, I saw that someone liked this post. Well if someone was selling an STS with a bad tranny, it wasn't me. After the swap, I had no issues. The car shifted smooth and quick, and ran really well.

The car was a Northstar. Getting to the top to bolts, I had to esentially tip the drive train back a little bit, and used a closed end wrench to break the torque on the top two, and then I have a small ratcheting stubby closed end wrench to get them out. The hardest part was that the bolt also went through a bracket that the electrical harness is zip tied to. All of this work was done from underneath the car, I don't think you could have gotten to it from above. I did have several bruises on my arms from getting up in there and getting those bolts out.

I have been out of the STS scene for a while, as we needed a larger car for the family. We sold the STS in August of 2013 and I picked up Tahoe as a family hauler. It was an older Tahoe, so paid cash. The wife hates the Tahoe with every fiber in her being, so we sold our Saturn Vue and recently picked up a 2006 SRX Northstar AWD. So while I am back in the Caddy scene I am not on the STS board too much. If anyone has any other questions, feel free to email me directly. same screen name (orange57) at gmail I'll do my best to provide any other info I can recall.